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by Arjan
Sat Jul 07, 2018 10:36 am
Forum: Bare metal, Assembly language
Topic: Bare metal malloc
Replies: 9
Views: 339

Re: Bare metal malloc

Here some baremetal examples for malloc:

https://github.com/rsta2/circle/blob/ma ... /alloc.cpp

https://github.com/vanvught/rpidmx512/b ... c/malloc.c

The malloc is independent of the MMU.
by Arjan
Wed Jul 04, 2018 2:45 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Multiple I2C devices interface
Replies: 4
Views: 221

Re: Multiple I2C devices interface

With respect to level-shifters; even when the I2C slave is running at 5V, then there could be no need for level-shifters. It depends on the factors a. If the I2C slave has pull-ups to 5V, b. The ViH min for the I2C slave is greater then 3V3
by Arjan
Wed Jun 27, 2018 3:30 pm
Forum: C/C++
Topic: C setup to Control the I2C GPIO pins.
Replies: 3
Views: 251

Re: C++ setup to Control the I2C GPIO pins.

stamechad11 wrote:
Wed Jun 27, 2018 2:26 pm
2: What C library is good to use for I2C control?
C library for Broadcom BCM 2835 as used in Raspberry Pi
http://www.airspayce.com/mikem/bcm2835/
by Arjan
Wed Jun 27, 2018 12:31 pm
Forum: Beginners
Topic: UART pins(TX, RX) on Raspberry Pi Zero W
Replies: 4
Views: 121

Re: UART pins(TX, RX) on Raspberry Pi Zero W

Nownuri wrote:
Wed Jun 27, 2018 9:34 am
1. Are the pins protected against ESD? What would be the rating of the ESD protection, for instance, 15kV?
In general, all the GPIO pins on the external header are directly connected to the SoC. At any time we should be careful in direct controlling of external devices.
by Arjan
Sun Jun 24, 2018 11:44 am
Forum: Automation, sensing and robotics
Topic: Help choosing parts for robot
Replies: 4
Views: 213

Re: Help choosing parts for robot

No need to switch to Arduino. The Raspberry Pi is a great platform for controlling devices.

Check Adafruit for servo solutions -> https://www.adafruit.com/?q=servo

There is also a great stepper motor board here -> https://roboteurs.com/products/slushengine
by Arjan
Sun Jun 24, 2018 9:56 am
Forum: Automation, sensing and robotics
Topic: Best relay board
Replies: 4
Views: 365

Re: Best relay board

dcaccount wrote:
Sun Jun 03, 2018 7:51 pm
I need a 8 relay board fully compatible with my Rpi3.

Can you please advise your recommendations?
Controlled by I2C or SPI -> http://www.bitwizard.nl/shop/expansion-boards/BigRelay
by Arjan
Sat Jun 23, 2018 8:48 pm
Forum: Beginners
Topic: convert aurdino code to python for raspberry pi
Replies: 2
Views: 103

Re: convert aurdino code to python for raspberry pi

venkatsai.laurel wrote:
Sat Jun 23, 2018 10:52 am
I want this code of VOICE CONTROLLER in aurdino to python which can be executed in raspberry pi
See append Running Arduino sketches on the Pi -> viewtopic.php?t=134928
by Arjan
Sat Jun 23, 2018 8:31 pm
Forum: Beginners
Topic: How to expand to 120 GPIO?
Replies: 9
Views: 230

Re: How to expand to 120 GPIO?

Hi, I have a project where I need to control 60LEDs, 60buttons, and 60LCD displays. When using addressable led's (WS28xx), then you just need one SPI MOSI pin. The 60 buttons can be configured in a matrix; scanning principle. Less GPIO's needed. Are the LCD display's controller with SPI, I2C? At an...
by Arjan
Sat Jun 23, 2018 8:26 pm
Forum: Troubleshooting
Topic: Control head light from rpi via dmx
Replies: 7
Views: 255

Re: Control head light from rpi via dmx

It is best to ask your question with the OLA users on https://groups.google.com/forum/#!forum/open-lighting

Then please do add the log for ola -l 4

Show that your output device is up-and-running. This can also be done using the OLA GUI.
by Arjan
Sat Jun 23, 2018 8:21 pm
Forum: Beginners
Topic: program for pi A+
Replies: 5
Views: 165

Re: program for pi A+

Will a program written for pi A+ work on pi 3B Program compatibility between Raspberry Pi models can not be guaranteed. Most of all, it depends on your program language.. When your program is written in a high-level language, and -not- programming directly to devices, then the program will most lik...
by Arjan
Sat Jun 23, 2018 7:08 pm
Forum: Bare metal, Assembly language
Topic: Assembly / C IDE that can remote compile / debug / run
Replies: 5
Views: 373

Re: Assembly / C IDE that can remote compile / debug / run

I was hoping to avoid having to build a cross compiler as that seems to be a major pain. I have a step-by-step instruction here -> http://www.raspberrypi-dmx.org/raspberry-pi-dmx512-rdm/development-environment However, you can also do a : apt install inutils-arm-none-eabi gcc-arm-none-eabi There is...
by Arjan
Fri Jun 22, 2018 6:16 pm
Forum: Bare metal, Assembly language
Topic: DMA configuration issue
Replies: 3
Views: 810

Re: DMA configuration issue

There is a good example for bare metal SPI DMA here -> https://github.com/rsta2/circle/blob/ma ... terdma.cpp
by Arjan
Wed Jun 20, 2018 7:05 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Send 64 bit from one Raspberry PI 3 B to another
Replies: 30
Views: 1085

Re: Send 64 bit from one Raspberry PI 3 B to another

jdb wrote:
Wed Jun 20, 2018 7:02 pm
Absent any sensible reason why the UART, or SPI is unsuitable...
Are you saying that the SPI Slave should work? If so, then please can you provide a pointer to code?
by Arjan
Sat Jun 16, 2018 5:13 pm
Forum: C/C++
Topic: Writing data to BCM2835 - SPI
Replies: 24
Views: 957

Re: Writing data to BCM2835 - SPI

Unfortunately the questions show that nothing has been learned from previous answers. There is a clear lack of understanding of SPI which should be understood after a look at wiki. Most of the questions are easily answered by looking at existing SPI code. I can only speak for myself but my patience...
by Arjan
Fri Jun 15, 2018 4:25 pm
Forum: C/C++
Topic: Writing data to BCM2835 - SPI
Replies: 24
Views: 957

Re: Writing data to BCM2835 - SPI

This code just ignores too many things - for example there are no "SPI commands" - some and it appears BCM hardware does , takes command + data in sequence. Or switching form "command " to data by toggling SS / CEx is not there either. Than "16 word" register would be useful for that. This is bare-...
by Arjan
Fri Jun 15, 2018 4:16 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: More BCM2835 / SPI questions
Replies: 15
Views: 642

Re: More BCM2835 / SPI questions

julyjim wrote:
Fri Jun 15, 2018 1:35 pm
I will try to modify my SPI_FIFO DATA to "send" only one bit and see what develops.
The AUX SPI has the possibilty to shift bits --> AUXSPI0/1_CNTL0 Register
by Arjan
Fri Jun 15, 2018 9:08 am
Forum: Bare metal, Assembly language
Topic: Circle - C++ bare metal environment (with USB)
Replies: 120
Views: 29517

Re: Circle - C++ bare metal environment (with USB)

rst wrote:
Wed Sep 27, 2017 6:22 am
Nevertheless there is an application of Circle networking for stage light environments (UDP-based ArtNet) which seems to work well.
I can confirm that Circle is a robust platform for UDP-based ArtNet and OSC
by Arjan
Fri Jun 15, 2018 8:51 am
Forum: C/C++
Topic: Writing data to BCM2835 - SPI
Replies: 24
Views: 957

Re: Writing data to BCM2835 - SPI

10.6.1 Polled a) Set CS, CPOL, CPHA as required and set TA = 1. b) Poll TXD writing bytes to SPI_FIFO, RXD reading bytes from SPI_FIFO until all data written. c) Poll DONE until it goes to 1. d) Set TA = 0. The above can be implemented as follows: void bcm2835_spi_writenb(const char* tbuf, const uin...
by Arjan
Fri Jun 15, 2018 8:43 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: More BCM2835 / SPI questions
Replies: 15
Views: 642

Re: More BCM2835 / SPI questions

To clarify - I am not using ioctl , just modified BCM2835 C library. Hi, I suppose you are referring to http://www.airspayce.com/mikem/bcm2835/ - a great library for low-level programming in Linux. I am using the SPI code for a long time (mainly on baremetal https://github.com/vanvught/rpidmx512/tr...
by Arjan
Wed Jun 13, 2018 5:22 pm
Forum: Troubleshooting
Topic: Control head light from rpi via dmx
Replies: 7
Views: 255

Re: Control head light from rpi via dmx

I suggest you might find something useful on this site: https://learn.adafruit.com because they focus on beginners with Arduino/Rpi. There is no DMX stuff on Adafruit. The best option to look for OLA information is the OLA website https://www.openlighting.org/ola/tutorials/ola-on-raspberry-pi/ I ha...
by Arjan
Wed Jun 13, 2018 6:31 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Send 64 bit from one Raspberry PI 3 B to another
Replies: 30
Views: 1085

Re: Send 64 bit from one Raspberry PI 3 B to another

Page 160 in https://www.raspberrypi.org/app/uploads/2012/02/BCM2835-ARM-Peripherals.pdf " The BSC interface can be used as either a Broadcom Serial Controller (BSC) or a Serial Peripheral Interface (SPI) controller. ... The SPI controller implements 3 wire serial protocol variously called Serial Pe...
by Arjan
Tue Jun 12, 2018 8:40 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Send 64 bit from one Raspberry PI 3 B to another
Replies: 30
Views: 1085

Re: Send 64 bit from one Raspberry PI 3 B to another

DougieLawson wrote:
Tue Jun 12, 2018 8:25 pm
Not with Linux, because there's no kernel driver for it.
Still the question, does the SoC support the SPI Slave functionality ? The I2C Slave is working nicely.
by Arjan
Tue Jun 12, 2018 8:23 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Send 64 bit from one Raspberry PI 3 B to another
Replies: 30
Views: 1085

Re: Send 64 bit from one Raspberry PI 3 B to another

https://www.raspberrypi.org/documentation/hardware/raspberrypi/spi/README.md That page describes the SPI Master interface. The SoC has also a I2C/SPI Slave interface at address (BCM2835_PERI_BASE + 0x214000). I've got the SPI Slave partially working. Hence I would like to know if it can work at all.
by Arjan
Tue Jun 12, 2018 6:01 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Send 64 bit from one Raspberry PI 3 B to another
Replies: 30
Views: 1085

Re: Send 64 bit from one Raspberry PI 3 B to another

GuruMeditation wrote:
Mon Jun 11, 2018 10:52 am
The RaspberryPI's hardware SPI does not support slave mode.
Do you have a formal written/link/reference for the statement above?

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